Resistance Training

Original Editor - User:Aditya Khachane Top Contributors - Aditya Khachane

Introduction

Resistance exercise

Resistance exercise is any form of active exercise in which dynamic or static muscle contraction is resisted by an outside force applied manually or mechanically. Resistance exercise, also referred to as resistance training, is an important component of a complete rehabilitation/exercise program to complement the widely known positive effects of aerobic training on health and physical capacities, potentially enhance the performance of motor skills, and reduce the risk of injury and disease. Resistance training is simply a form of training in which you're working against some type of force that "resists" your movement. We are familiar with weightlifting, but other kinds of activities fall under the heading of resistance training, including bodyweight exercises, dragging sledges, running with parachutes, and even movement in the water. More resistance also means your muscles have to work harder.

Principles

Guiding principles to develop a resistance training program are:

• Overload principle is a guiding principle of exercise prescription that has been one of the foundations on which the use of resistance exercise to improve muscle performance is based. Simply stated, if muscle performance is to improve, a load that exceeds the metabolic capacity of the muscle must be applied — that is, the muscle must be challenged to perform at a level greater than that to which it is accustomed.

• SAID principle (specific adaptation to imposed demands ) suggests that a framework of specificity is a necessary foundation on which exercise programs should be built. This principle applies to all body systems and is an extension of Wolff's law (body systems adapt over time to the stresses placed on them).

• Reversibility principle suggests that adaptive changes in the body’s systems, such as increased strength or endurance, in response to a resistance exercise program are transient unless training-induced improvements are regularly used for functional activities or unless an individual participates in a maintenance program of resistance exercises.

Determinants of Resistance Training

Many elements determine whether a resistance training program is appropriate, effective, and safe. This holds when resistance training is part of a rehabilitation program for individuals with known or potential impairments in muscle performance or when it is incorporated into a general conditioning program to improve the level of fitness of healthy individuals. Consistent with the SAID principle, these elements of resistance training must be specific to the individual's desired functional goals.

• Alignment of segments of the body during exercise
• Stabilization of proximal or distal joints to prevent substitution
  
• Intensity: the exercise load (level of resistance)
• Volume: the total number of repetitions and sets in an exercise session
• Exercise order: the sequence in which muscle groups are exercised during an exercise session
• Frequency: the number of exercise sessions per day or week
• Rest interval: time allotted for recovery between sets and sessions of exercise
• Duration: total time frame of a resistance training program
• Mode of exercise: type of muscle contraction, position of the patient, form (source) of resistance, arc of movement, or the primary energy system utilized
• Velocity of exercise
• Periodization: variation of intensity and volume during specific periods of resistance training
• Integration of exercises into functional activities: use of resistance exercises that approximate or replicate functional demands

Contraindications

Resistance training is contraindicated only in a few instances. Adverse effects from resistance training can be avoided by carefully selecting the appropriate mode of exercise and keeping the initial intensity of the exercise at a low to moderate level.

• Pain experienced during active unresisted movements in the muscles or joints is a clear contraindication to initiate resistance training. If a patient experiences pain that cannot be eliminated by reducing the resistance, training should be stopped.
• Dynamic and static resistance training is contraindicated in the presence of inflammatory neuromuscular disease. Dynamic resistance exercises are contraindicated in the presence of acute inflammation of a joint as it can irritate the joint and cause more inflammation.
• Severe cardiac or respiratory diseases or disorders associated with acute symptoms contraindicate resistance training.

Adaptations

Resistance training can have various adaptations to different systems of our body:

• Skeletal muscle adaptations include muscle fibre hypertrophy (greatest in type IIB fibres), possible hyperplasia of muscle fibres, fibre type composition remodelling of type IIB to type IIA, no change in type 1 to type II distribution, decrease or no change in capillary bed density, decrease in mitochondrial density and volume.
• Neural system adaptations involve motor unit recruitment (increase in number of motor units firing), increased rate of firing (decreased twitch contraction time) and increased synchronization of firing.
• Connective tissue adaptations like increased tensile strength of tendons, ligaments, and connective tissue in muscle, bone mineral density; no change or possible increase in bone mass.
  

Related Pages

• Strength Training
• Therapeutic Exercise
• Strength and Conditioning